title: A randomised controlled trial investigating the effect of vitamin B12 supplementation on neurological function in healthy older people: the Older People and Enhanced Neurological function (OPEN) study protocol [ISRCTN54195799].
abstract: BACKGROUND
  Vitamin B12 deficiency is common in older people and the prevalence increases with age. Vitamin B12 deficiency may present as macrocytic anaemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. The diagnosis and indications for treatment are clear for individuals with low plasma levels of vitamin B12 in the setting of megaloblastic anaemia and neuropathy, but the relevance of treatment of vitamin B12 deficiency in the absence of such clinical signs is uncertain.
  
  
  METHODS
  The aim of the present study is to assess whether dietary supplementation with crystalline vitamin B12 will improve electrophysiological indices of neurological function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of anaemia. To test this hypothesis we designed a randomized double-blind placebo-controlled trial involving 200 older people aged 75 years or greater who were randomly allocated to receive either a daily oral tablet containing 1 mg vitamin B12 or a matching placebo tablet. The primary outcome assessed at 12 months is change in electrophysiological indices of peripheral and central neurosensory responses required for mobility and sensory function. We here report the detailed study protocol.
  
  
  CONCLUSIONS
  In view of the high prevalence of vitamin B12 deficiency in later life, the present trial could have considerable significance for public health.
authors.affiliation: Department of Nutrition and Public Health Intervention Research, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK. alan.dangour@lshtm.ac.uk
authors.forename: Alan D
authors.initials: AD
authors.lastname: Dangour
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Allen
authors.forename: Robert
authors.initials: R
authors.lastname: Clarke
authors.forename: Diana
authors.initials: D
authors.lastname: Elbourne
authors.forename: Nicky
authors.initials: N
authors.lastname: Fasey
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Fletcher
authors.forename: Louise
authors.initials: L
authors.lastname: Letley
authors.forename: Marcus
authors.initials: M
authors.lastname: Richards
authors.forename: Ken
authors.initials: K
authors.lastname: Whyte
authors.forename: Kerry
authors.initials: K
authors.lastname: Mills
authors.forename: Ricardo
authors.initials: R
authors.lastname: Uauy
mesh_terms: D000368:Aged; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D009424:Nervous System Physiological Phenomena / Q000187:drug effects*; D009431:Neural Conduction / Q000187:drug effects; D014805:Vitamin B 12 / Q000627:therapeutic use*
chemical_list: D014805:Vitamin B 12